Centrifugal strainer for wood-pulp and cellulose.



APPLICATION FILED JULY 29, I913.

Patented J uly 6, 1915.

COLUMBIA PLANOORAPH (20., \VASHXNGTDN. D4 c.

barren snares in ar ricer HALLGBIM TI-IORESEN, OF VES'IRE AKER, NEARGHBIS'IIANIA, AND JONAS CORNELIUS FALCH, 0F CHRISTIANIA, NORWAY; SAIDTHORESEN ASSIGNOR TO NILS ROTH HEYEH'DAHL, OF CHRISTIANIA, NOR-'WAY.

GENTRIF'UGAL STRAINER F03, WOOD-PULP AND CELLULOSE.

Application filed July 29, 1913.

To all whom it may concern:

lie it known that we, HALLGRIM Tnonn- SEN and Jonas CORNELIUS FALGH,subjects of the King of Norway, residing at Gunvang, Vestre Alter, nearChristiania, and L fikeberggaten 5, Christiania, Norway, have inventedcertain new and useful Tnr provements in Centrifugal Strainers for-Wood-Pulp and Cellulose; and we do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to lettersor figures of reference marked thereon, which form a part of thisspecification.

This invention has for its object a centrifugal sorting apparatus.

In the type of centrifugal sorting apparatus now in use for wood pulpsand cellulose having a stationary cylindrical strainer and a centrifugalfan on a horizontal shaft it proves that the power consumed for drivingthe fan is relatively very large in comparison with the work done. Thisis owing partly to an uneven distribution of the pulp water around thefan and partly to the shock producing action of the pulp water againstthe fan.

The present invention now has for its object to produce an arrangementwhereby the pulp water is distributed as uniformly as possible aroundthe whole strainer plate and whereby the supply of pulp water to the fanrotating with great velocity is effected without the production ofshocks and consequently with a good hydraulic efficiency. Further thesaid arrangement makes it possible to effect an automatical control ofthe supply openings, whereby the level in the supply channel ismaintained constant so that no changes in the velocity of the pulp watersupplied to the fan take place. The velocity of the pulp water suppliedto the fan is namely proportional with the square root of the pressurein the supply chamber and it is therefore of importance to maintain thesaid velocity constant.

The invention is illustrated in the accompanying drawing in which Figure1 is a vertical sectional elevation through a sorting apparatus, Fig. 2illus Specification of Letters Patent.

Patented July 6, 1915.

Serial No. 781,708.

trates the arrangement of the vanes or wings of the centrifugal fan.

The pulp water is supplied through the openings (Z to the one end of thefan at the periphery. The inlet openings (Z, which are distributed insuch manner as to obtain an even distribution of the pulp water are inconnection with one or more closed chambers, in which the pulp waterstands under a pressure determined by the level of the pulp water in thesupply channel with which the said chamber or chambers directlycommunicate.

In order to obtain a smooth entrance (without shocks) of the pulp waterinto the fan the wings a of this latter are on the supply end arrangedunder such an angle with the direction of rotation that the supplyvelocity (to) (which is determined by the pressure in the supplychamber) and the peripherical velocity (y) of the fan and theinclination line of the wings form a closed triangle as shown in Fig. 2.In this manner the best possible hydraulic efliciency is obtained. Asshown in Fig. 2 it is only in that end, where the pulp water is suppliedthat the wings are given the said strongly inclined position. At thatpart (c) of the wings where the straining is to take place the wings areonly given such inclination as is necessary in order to impart to thepulp an axial movement and at the portion 7) the wings are bent backwardrelatively to the direction of rotation in order to effect the throwingaway of the fibers, which have not passed through the strainer. In orderthat the said smooth entrance of the mass shall take place it isnecessary that the supply velocity of the pulp water is main tained asconstant as possible during the working. To obtain this the supplyopenings are arranged so as to be controlled and are connected with thesupply channel in such manner for instance by means of a float that thelevel of the liquid and accordingly also the supply velocity ismaintained constant.

When the liquid level in the supply channel is raised the float is alsoraised and by a lever and link arrangement, this upward movement of thefloat effects a movement of the ring controlling the entrance channelsin such manner that the supply openings are enlarged. The quantity ofliquid entering through the channels cl is thereby increased. The levelof liquid in the pulp channel is then brought down to the normal height.The resulting lowering of the float then effects a reduction of thequantity of pulp supplied through (Z. The controlling arrangementdescribed above may of course be substituted by any other suitable meansfor maintaining a constant velocity of the pulp jet passing through thechannels d toward the edges of the fan Wings a. The number and area ofthe openings (Z may, of course, also be varied accordingto thecircumstances.

We claim:

In a centrifugal strainer for Wood pulp and cellulose having astationary perforated member and a rotary member on a horizontal shaftsurrounding said perforated member, means for driving the rotary memberat a predetermined speed, and means for supplying liquid pulp in anaxial direction to the rotary member near its periphery and ata'constant head, the rotary member having blades opposite the supplyopening, the latter having their initial portio-ns a inclined to theaxis at an an gle determined by the speed of rotation at the head atWhich the pulp is supplied to receive the material and increase itsvelocity in the direction of the axis, the acceleration beingsubstantially harmonic, the blades also having portions 0 and b torotate the material and throw it against the screen and to expel theunstrained portion respec tively.

In testimony that'We claim the foregoing as our invention, We havesigned our names in presence of tWo subscribing Witnesses.

HALLGRIM THORESEN. JONAS CORNELIUS FALGH.

Witnesses:

M. E. GUT'roRENsEN, HENRIKKA HAIGH SOl-IMlDl.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

